It’s what you’re buying when you buy hybrid, the place where the premium lives and the thing you better be happy with after you get the car home. When push meets shove, a hybrid is all about powertrain –- the rest is all sugar frosting and happy faces. These complicated systems work more or less the same way: By connecting electric motors to an internal combustion engine, automakers can put smaller, more efficient engines in larger vehicles –- thus reducing fuel consumption, and, as a result, pollution. There are two basic types of hybrid systems. The “partial hybrid” uses electric motors to provide power to the engine to aid in acceleration. With a partial hybrid, the internal combustion engine must always be in operation when the vehicle is moving. Partial hybrids provide a better driving experience for less fuel expense and lower pollution, though the pollution side of that argument can be argued.

There’s also the so-called “full hybrid,” which significantly reduces pollution and improves fuel economy because it can operate solely on electric power. When a full hybrid vehicle is at a stoplight or stuck in traffic, for example, the internal combustion engine will click off and the car will run exclusively on electric power. When red goes green or traffic speeds pick up, the driver steps on the accelerator, the engine comes to life –- courtesy of a powerful starter motor -- and off you go. The benefit to a full hybrid is as obvious as the brown crud that hovers over our major cities. No idling engine equals far less pollution and much improved gas mileage.

Based on what it does, what it is and how well it delivers on the hybrid promise of lower fuel bills and reduced emissions, the winner was clear: the 2005 Toyota Prius.